Machine for making leaf-springs



I. L. R. DORVILLE. MACHINE FOR MAKING LEAF SPRINGS.

APPLICATION FILED JAN. 20, I920. '1,3'75,G38, Pat nted Apr- 19,1921.

3 SHEETS-SHEET VENTOR wdz . I F I ymf F UE

T. L. R. D'ORVILLE.

MACHINE FOR MAKING LEAF SPRINGS.

APPUCA'HGN FILED JANZ0,19ZO.

1,375,038, Patented Apr. 19, 1921.

3 SHEETS-SHEET 2.

I T. L. R DORVILLE. MACHINE FOR MAKING LEAF SPRINGS.

APPLICATION FILED JAN-20, I920.

Patented Apr. 19, 1921.

3 SHEETS-SHEET 3- Pennsylvania,

- while the upper roll is a rs stars 'rneononn I). a- DORVILLE, orsnwicirrnr, rnnivsrrvanm, ssieivon T0 serum- ARI) STEEL SPRING- TION 0EPENNSYLVANIA.

COMPANY, oroonnoronrs, PENNSYLVANIA, A. 00

I MACHINE FOE T-IIAKING LEAF-SPRINGS.

newness.

Z '0 all "(17710777, it may concern Be it known that "l, THEODORE L. R.DOnviLLn, a subject of the Queen of the Netherlands, and residentofSewickley, in the county of Allegheny and State of have invented a newand usein Machines for Making I do hereby declarethe and exact defulImprovement Leaf-Springs; and following to, be a full, clear, scriptionthereof,

My invention relates to the production of steel leaf springs, and it hasfor its object to provide a simple and effective machine for bendingspring blanks by a processof cold rolling.

The machine which forms the subject of the present. invention isparticularlyv designed to carry out the steps of the process 7 describedand claimedin my co-pending application for Letters Patent Serial No.352,746, filed January 20, 1920.

My machine consists, in general, of a set of three parallel andti'iangularly arranged bending rolls, two of the rolls being ofrelatively small diameter, and being set closely together in ahorizontal plane. The third roll is disposed above'and between the twofirst-named rolls, and larger diameter. The tively driven and aretudinal serrations on lower rolls are posiprovided with longitheirworking faces, loosely mounted for rotation and performs .the functionof a former or platen roll. Suitable means are provided for adjustingupper roll from the other rolls, and such adjustment may be effectedeither while the machine is at rest or during the rolling of a blank.

In making springs and parts that must undergo bending and similarfatiguing stresses, it has thought necessary to avoid any operationwhich 'will distort the interior structurev of the metal. Cold workingmethods have therefore been carefully avoided. In mak ing ellipticalleaf springs, for example, the

universal practice has been to heat the spring blanks until theirelasticity is destroyed, to press the blanks between formers or byforming over patterns'with tongs, and then to quench the blanks withwater while thus held. When this process is operated on a large scale,-extensive furnace arrange,

is of considerably the position of. the

by moving it toward or away other mechanical hitherto been 1Specification of Letters latent. Patented Apr. 19, 1921 Applicationfiled January 20, 1920. Serial No. 352,747. r

ments are necessary for heating the blanks and considerable amounts oftime and labor are consumed,

l have discovered the somewhat surprising fact that, although coldworking strains the structure of steel and therefore produces a materialwhich would be supposed not to withstand fatigue, a proper heattreatment will restore to the cold-worked steel: an unstrained structurewhich is even superior to the structure present in springs produced byordinary hot-working methods. lhe spr ngs thus produced are moreefficient than springs produced by hot-pressing methods, because thehot-pressing method in which the blank is held in its distorted positionand quenched :with water produces internal defects in the steel whichcannot thereafter be cured by heat treatment.

For a better understanding of my invention, reference may now be had tothe accomp anying drawings, in which Figure 1 is a sideelevational viewof a bending machine, constructed in accordance with my invention; Fig.2 is a longitudinal sectional view taken centrally through the bendingrolls;

Fig. 3 is a transverse vertical sectional View,

the section being taken substantially alongthe line 3-3, 2; Fig. t is afragmentary side view showing the driving gears for the tween a blankand the bending rolls at the beginning of the bending operation; andFig. 7 is 6 showing the blank at the moment when the rolling is nearlycompleted.

a diagrammatic view si'milarto Fig.-

Referringto'Figs. 1 to 5, inclusive, the' bending machine consists of aframe 1 which supports near one of itsends a housing 2 in whicharemounted two lower bending rolls 8 and l preferably having their axesin a common horizontalv plane, and an upper bending roll 5, the axis ofwhich is disposed above and midway between the axes of the twolowerrollers. The lower'rolls 3 and 4 are mounted on shafts 6 and 7,respectively, which are held in bearings that-are rigidly carried in thehousings 3, roller bearings 8 being suitably provided same directionfrom a' 'power shaft v9 disposed below the. rolls and fil llficted todrive for both of the rolls 3 and at. The lower rolls are driven in thei 26 upon of the housing 3.

- is a housing 23 hand wheel. 20, the

.ing block the rolls by means of a spur gear 10 keyed to the shaft 9 andspur gears 11 and 12 meshing with the gear 10 and keyed to the shafts 6and 7, respectively. The power shaft 9 is driven in a manner to bedescribed in detail below. The upper roll 5 is loosely mounted. forrotation in roller bearings 15 that are supported in a block 16 which.is mounted in vertical slides within the housing 3, the purpose of thisarrangement being to enable the roller 5 to be vertically adjusted inorder to var Y the distance or clearance between the upper roll and thetwo lower rolls in order that the curvature of the blanks fed throughthe machine may be altered to suit requirements.

The adjustment of the vertically sliding block 16 is effected by meansof a coarse adjusting screw 17 and a fine adjusting screw 18. The coarsescrew 17 is formed on the lower end of a vertical shaft 19 which carries near its upper end a hand wheel 20 and the screw 17 engages asuitable screw thread which may be formed in the sliding block 16 or asshown in Fig. 2, in a separate nut 21 that is anchored to the block asby means of a screw 22 for the purpose of cheaper replacement cost whenthe screw threads become worn.

Surrounding the screw shaft 19 between the screw threads 17 and the handwheel 20 which incloses a ball thrust washer 2e for preventing the axialdisplacement of the shaft 19. The housing 23 is also provided with ahand lever 25 and with a downwardly extending annular portion which areformed the fine screw threads 18 .which engage corresponding screwthreads formed in a steel cap 2'? bolted to the top of the housing 3. Itwill beevident that when the hand lever 25 remains stationary and thehand wheel 20 is turned, the rotationof the screw 17 will. cause thesteel block 16 to be lowered or raised, thus providing the rough orcoarse adjustment of the upper. roller. When thehand wheel 20 isprevented from rotating and the lever 25 is turned, it will also beevident that the lever 25 carr eswlth it the housing 23, m-

cluding'theiine screw threads 18, whereby the complete assembly,constituted by the vertical screw 19, with. its ball thrust, and thehousing 23 will be raised or lowered carrying with it the slid- 16 andthe upper roll 5.

In order toipre'vent the hand wheel 20 from rotating during the fineadjustment of the roller 5, I provide the hand wheel 20 with a-toothedquadrant 28 engaged a spring pressed plunger 29 inclosed within atubular housing 30 carried by the cap 27 Thele'ver 25 is similarlyprovided with means for preventing it from rotatirigfsuch .means beingbest shown in Fig.5 and'consistingofa quadrant 31 carthe unit pressureon the surface,

ried by a bracket 32 and engaged with a spring-pressed plunger 33inclosed within a housing 34: attached to the hand lever 25. Since thehand lever 25 controls the line screw threads 16, it is obvious that arelatively large angular displacement of the lever will result in asmall amount of vertical adjustment of theroll 5. F or example, in onemachine which I have constructed, each notch on the hand-wheel 20corresponds to approximately .005 inches vertical displacement of theroller, whereas the total swing of the hand lever 25 through an angle of90 will amount to a displacement of 0.025 inches, so that the total fineadjustment range is equivalent to 5 notches of the coarse adjustment, I

In order that the curvature imparted to the spring blanks may be asaccurate as pos sible, it is desirable to reducethe axial distancebetween the two lower rolls 3 and 4: to the strictest minimum consistentwith structural requirements. Otherwise the ends of the spring blankswill always be left fiat for an appreciable distance. As a result ofthis close arrangement of the lower rolls, the pressures upon the rollsare of considerable magnitude and result in correspondingly highpressures on the bearing surfaces. F or this reason it is desirable tomake use of heavy-duty roller bearings in orderto produce a compactmachine and avoid bearing 1 and lubrication difficulties.

It'will be observed that the lower rolls, together with their'respectiveshafts, bearings and gears are designed as a unit, which may be quicklydisassembled in a body for the purpose of rapid replacement. Since. theamount of surface wear upon therollsis comparatively rapid, I providethe lower rolls with replaceable wearing surfaces consisting of sleeves35 that are slipped over the rolls proper and are secured to the roll bymeans of keys 86.

The working sleeves 35, as best shown in Figs. 2, 6 and 7 are providedwith longitudinal serrations which constitute. an important feature ofthe machine. 7 These serrations performtwo functions. First, by reducinthe roller surface in contact with the blank at any one moment, they incease thereby squeezing off any oil or greasyfilm that may exist upon thesurface of the blank, the serrations also providing the necessarychannels forevacuating grit'and scale. slippage is thus obvlated and thedrive upon thethe serrations engaging the end oftheblank I tends toraise it and carry it up over the top of the roll. If it were not forthis action of the serrated r0114, heavy and tough the blank,

preferably formed.

points, as shown in Fig. 7, the drive'being continuously transmittedvfrom the "same points, and the curvature of the blank s thus keptaccurate. v v

''The power shaft 9 which drives the lower bending rollers may 'bedrivenin any suitable manner. As shown'in Figszland 5, the drivingmeanscompr1ses an electric motor d0 which delivers its power,

epicyclic speed reduction gear box a1 and a two-speed spur-gearbox 42,'to a'bevel pinion e3 which meshes'with a bevel gear wheel i l-that ismounted on a countershaft 45. The counter-shaft 45. also carries a chainsprocket ar'oundwhich travels a silent chain or link belt 46 whichalsopasses around an upper sprocket 47 that is secured to the powershaft 9. 1 Y

The two-speed gear box a2 is provided in order that the operator mayvary the speed of the bending rolls to increase production, the lowerspeed being usedfor bending short plates, while the high speed is moreeconomical when bending long plates. The change-speed mechanism iscontrolled by a hand lever 48 provided with a notched quadrant 4.9 andbolted to 'the'side of the frame 1.

It is important that'the blanks be fed straight to the bending rolls, asotherwise warping may occur and the blocks may jam against the sides ofthe. housing. In order to properly guide the blanks, I provide movablejaws 50, Fig. 5, which are actuated by means of a right and left handscrew. 51 controlled by a small hand wheel 52 provided with a suitablestop device 53. The guides 50 provide for positively centering V whichnot only insures proper bending of the plate itself, but also equalizesthe pressureon the roller bearings. Also, as the bending rollers wear,it is evident that the lower roller surfaces will not be 'of uniformdiameter throughout their length, and it is not desirable to have oneside" of the blank ride over a larger diameter than the other side. Thiswould be possible if the blank should be fed into the machine otherwisethan centrally with respect to the rolls. p 4

The upper roll 5, the surface of which is of chilled steel, is made aslarge as possible in order to increase the available wearing surface andproduce a longer life before replacement becomes necessary. The largeradius of curvature also has a tendency to allow the blank to wrapitself smoothly around the surface of the roll, thus avoiding theliability of kinks which would impair the quality] of the product. 7 r

In the operation of themachine which I bending rolls; p I desiredtoprovide blanks with a' compound 170 during the operation of rolling eachblank,-

through an Y in triangular form.

ever, not been applied to the manufacture of have shown and described,theblanks are fed through the guides 50, and between the If, asis'oftenthefcase, it is curvature, ,the upper roll" is moved verticallythis vertical adj ust ment being produced by turning the hand lever 25:or the'hand wheel 20 in accordance with the change in curvature that isdesired." This'adjustment of the upper roll during the rolling operationmay be" performed eithermanually or auto matically, as desired.

The blanks which carrying out my process are composedof steel havingbanelastic limit ofbetwe'en 10,000 pounds and 90,000 pounds per squareinch, though, as in the caseiof alloy-steel blanks, the initial elastic.limit may rise as high as 120,000j"poundsper square} inch. After theblanks are rolled "they are heated in a suitable tempering furnace to atemperature suitably between 1l80 F. and 1600 F. and are then quenchedin oil. This process results in a final elastic limit of the finishedproduct varying between 180,000

poundsand 200,000 pounds.

I prefer to employ have been provided in which the bending is effectedby means of threev rollers arranged This method has, howsprings, becauseof the prevailing belief, indicatedabove, that rolling or other coldworking cannot be used to produce a spring which is to be subjected tofatiguing stresses. While the machine which I have herein shownand'described embodies the construction which I prefer at present toemploy, it is obvious that various changes in the construction andarrangement of its parts may be made without' departing from myinvention. I therefore desire that my in vention be understood toinclude all such changes and adaptations asfall Within. the

scope of the appended clalms.

What I claim is:

1. A machine for bending leaf springs and the like comprisingthreeparalleland triangularly arranged bending rolls, a slid able block forrotatably supporting one of the said rolls, a shaft in screw-threadedsupporting engagement with the 'said block,

.means for supporting the said shaft from "screw threads of a differentpitch from the screw threads on the said shaft and means forindependently turning either the said shaft or the said shaft-support,whereby the said block andthe said roll may be given either a roughadjustment or a fine adjustment toward or away from the other two rolls;7 I I 2. A machine for bending leaf springs and the like comprising aframe, three parallel and triangularly arranged bending between the twofirst-named rolls, a block for rotatably supporting the said upper roll,vertical ways in the said frame for guiding rolls carried by the saidframe, two of the said rolls being horizontally side by side and thethird roll being disposed above and the said block, a vertical shafthaving a screw-threaded end in supporting engagement with thesaid block,means forsupporting the said vertical shaftin the said frame by means ofscrew threads of smaller pitch than the screw threads on" the saidshaft, means for independently turning either the said shaft or the saidshaft support, whereby the'said block and the said roll may be giveneither a rough vertical adjustment or a fine vertical adjustment,

and means for severally locking the said turning means. v

3. A machine for bending leaf springs and thelike comprising a frame',anadjustable. bending roll carried by the said frame 7 screw threads ofsmaller pitch than the screw threads upon the said shaft, a hand wheelsecured to the upper end of the said shaft, a handle extending laterallyfrom the said housing, and means for releasably locking the said handwheel and the said handle in position.

In testimony whereof, I the said THEO- DORE L. R. DORVILLE,have'hereunto setmyv hand.

THEODORE L. R. DiORVILLE. Witnesses WALTER C. EIssLER, WAYNE R. MOORE.

